How to stop mail duplication

(Mail proxy is feudora).
In our office if a mail is received by a steno,a copy has to goto her manager,in turn her manger's copy goes to GM, and GM's copy goes to RM.the proper aliases have been configured but the problem is each one receives as many copies.(in this case each one is receiving 4 copies).
What setting will I have to do in proxy mail server, so that they get only 1 copy of the mail.

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